Cavity optomagnonics with magnetic textures: coupling a magnetic vortex to light

TL;DR

This paper explores the coupling between light and magnetic vortex excitations in a cavity optomagnonic system, revealing tunable interactions with potential for quantum information applications.

Contribution

It introduces a novel cavity-optomagnonic setup with a magnetic vortex, analyzing the spatial structure and tunability of light-magnon coupling in textured magnetic systems.

Findings

Coupling strength can be tuned by external magnetic fields.

Predicted cooperativity of approximately 0.01 at maximum photon density.

Rich spatial structure of optomagnonic interactions.

Abstract

Optomagnonic systems, where light couples coherently to collective excitations in magnetically ordered solids, are currently of high interest due to their potential for quantum information processing platforms at the nanoscale. Efforts so far, both at the experimental and theoretical level, have focused on systems with a homogeneous magnetic background. A unique feature in optomagnonics is however the possibility of coupling light to spin excitations on top of magnetic textures. We propose a cavity-optomagnonic system with a non homogeneous magnetic ground state, namely a vortex in a magnetic microdisk. In particular we study the coupling between optical whispering gallery modes to magnon modes localized at the vortex. We show that the optomagnonic coupling has a rich spatial structure and that it can be tuned by an externally applied magnetic field. Our results predict cooperativities at maximum photon density of the order of $\mathcal{C}\approx10^{-2}$ by proper engineering of these structures.